Xp21 muscular dystrophy due to X chromosome inversion.

Two brothers with Duchenne muscular dystrophy have an inversion of the X chromosome, 46, Y, inv(X) (p11.2p21.2). Because their mother is an unaffected carrier of the inversion, this confirms that maternal passage of a structurally abnormal X chromosome can cause dystrophinopathy in males. Our experience suggests that as well as molecular genetic analysis, karyotyping can be useful in Xp21 muscular dystrophy.